Alright, let's solve this math problem step by step. First, we have the number 503. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 158. So, we're going to take the number 503 and add it to itself 158 times.
Step 1: 0 + 503 = 503
Step 2: 503 + 503 = 1006
Step 3: 1006 + 503 = 1509
Step 4: 1509 + 503 = 2012
Step 5: 2012 + 503 = 2515
Step 6: 2515 + 503 = 3018
Step 7: 3018 + 503 = 3521
Step 8: 3521 + 503 = 4024
Step 9: 4024 + 503 = 4527
Step 10: 4527 + 503 = 5030
Step 11: 5030 + 503 = 5533
Step 12: 5533 + 503 = 6036
Step 13: 6036 + 503 = 6539
Step 14: 6539 + 503 = 7042
Step 15: 7042 + 503 = 7545
Step 16: 7545 + 503 = 8048
Step 17: 8048 + 503 = 8551
Step 18: 8551 + 503 = 9054
Step 19: 9054 + 503 = 9557
Step 20: 9557 + 503 = 10060
Step 21: 10060 + 503 = 10563
Step 22: 10563 + 503 = 11066
Step 23: 11066 + 503 = 11569
Step 24: 11569 + 503 = 12072
Step 25: 12072 + 503 = 12575
Step 26: 12575 + 503 = 13078
Step 27: 13078 + 503 = 13581
Step 28: 13581 + 503 = 14084
Step 29: 14084 + 503 = 14587
Step 30: 14587 + 503 = 15090
Step 31: 15090 + 503 = 15593
Step 32: 15593 + 503 = 16096
Step 33: 16096 + 503 = 16599
Step 34: 16599 + 503 = 17102
Step 35: 17102 + 503 = 17605
Step 36: 17605 + 503 = 18108
Step 37: 18108 + 503 = 18611
Step 38: 18611 + 503 = 19114
Step 39: 19114 + 503 = 19617
Step 40: 19617 + 503 = 20120
Step 41: 20120 + 503 = 20623
Step 42: 20623 + 503 = 21126
Step 43: 21126 + 503 = 21629
Step 44: 21629 + 503 = 22132
Step 45: 22132 + 503 = 22635
Step 46: 22635 + 503 = 23138
Step 47: 23138 + 503 = 23641
Step 48: 23641 + 503 = 24144
Step 49: 24144 + 503 = 24647
Step 50: 24647 + 503 = 25150
Step 51: 25150 + 503 = 25653
Step 52: 25653 + 503 = 26156
Step 53: 26156 + 503 = 26659
Step 54: 26659 + 503 = 27162
Step 55: 27162 + 503 = 27665
Step 56: 27665 + 503 = 28168
Step 57: 28168 + 503 = 28671
Step 58: 28671 + 503 = 29174
Step 59: 29174 + 503 = 29677
Step 60: 29677 + 503 = 30180
Step 61: 30180 + 503 = 30683
Step 62: 30683 + 503 = 31186
Step 63: 31186 + 503 = 31689
Step 64: 31689 + 503 = 32192
Step 65: 32192 + 503 = 32695
Step 66: 32695 + 503 = 33198
Step 67: 33198 + 503 = 33701
Step 68: 33701 + 503 = 34204
Step 69: 34204 + 503 = 34707
Step 70: 34707 + 503 = 35210
Step 71: 35210 + 503 = 35713
Step 72: 35713 + 503 = 36216
Step 73: 36216 + 503 = 36719
Step 74: 36719 + 503 = 37222
Step 75: 37222 + 503 = 37725
Step 76: 37725 + 503 = 38228
Step 77: 38228 + 503 = 38731
Step 78: 38731 + 503 = 39234
Step 79: 39234 + 503 = 39737
Step 80: 39737 + 503 = 40240
Step 81: 40240 + 503 = 40743
Step 82: 40743 + 503 = 41246
Step 83: 41246 + 503 = 41749
Step 84: 41749 + 503 = 42252
Step 85: 42252 + 503 = 42755
Step 86: 42755 + 503 = 43258
Step 87: 43258 + 503 = 43761
Step 88: 43761 + 503 = 44264
Step 89: 44264 + 503 = 44767
Step 90: 44767 + 503 = 45270
Step 91: 45270 + 503 = 45773
Step 92: 45773 + 503 = 46276
Step 93: 46276 + 503 = 46779
Step 94: 46779 + 503 = 47282
Step 95: 47282 + 503 = 47785
Step 96: 47785 + 503 = 48288
Step 97: 48288 + 503 = 48791
Step 98: 48791 + 503 = 49294
Step 99: 49294 + 503 = 49797
Step 100: 49797 + 503 = 50300
Step 101: 50300 + 503 = 50803
Step 102: 50803 + 503 = 51306
Step 103: 51306 + 503 = 51809
Step 104: 51809 + 503 = 52312
Step 105: 52312 + 503 = 52815
Step 106: 52815 + 503 = 53318
Step 107: 53318 + 503 = 53821
Step 108: 53821 + 503 = 54324
Step 109: 54324 + 503 = 54827
Step 110: 54827 + 503 = 55330
Step 111: 55330 + 503 = 55833
Step 112: 55833 + 503 = 56336
Step 113: 56336 + 503 = 56839
Step 114: 56839 + 503 = 57342
Step 115: 57342 + 503 = 57845
Step 116: 57845 + 503 = 58348
Step 117: 58348 + 503 = 58851
Step 118: 58851 + 503 = 59354
Step 119: 59354 + 503 = 59857
Step 120: 59857 + 503 = 60360
Step 121: 60360 + 503 = 60863
Step 122: 60863 + 503 = 61366
Step 123: 61366 + 503 = 61869
Step 124: 61869 + 503 = 62372
Step 125: 62372 + 503 = 62875
Step 126: 62875 + 503 = 63378
Step 127: 63378 + 503 = 63881
Step 128: 63881 + 503 = 64384
Step 129: 64384 + 503 = 64887
Step 130: 64887 + 503 = 65390
Step 131: 65390 + 503 = 65893
Step 132: 65893 + 503 = 66396
Step 133: 66396 + 503 = 66899
Step 134: 66899 + 503 = 67402
Step 135: 67402 + 503 = 67905
Step 136: 67905 + 503 = 68408
Step 137: 68408 + 503 = 68911
Step 138: 68911 + 503 = 69414
Step 139: 69414 + 503 = 69917
Step 140: 69917 + 503 = 70420
Step 141: 70420 + 503 = 70923
Step 142: 70923 + 503 = 71426
Step 143: 71426 + 503 = 71929
Step 144: 71929 + 503 = 72432
Step 145: 72432 + 503 = 72935
Step 146: 72935 + 503 = 73438
Step 147: 73438 + 503 = 73941
Step 148: 73941 + 503 = 74444
Step 149: 74444 + 503 = 74947
Step 150: 74947 + 503 = 75450
Step 151: 75450 + 503 = 75953
Step 152: 75953 + 503 = 76456
Step 153: 76456 + 503 = 76959
Step 154: 76959 + 503 = 77462
Step 155: 77462 + 503 = 77965
Step 156: 77965 + 503 = 78468
Step 157: 78468 + 503 = 78971
Step 158: 78971 + 503 = 79474

So, 503*158 = 79474